LexusADL

morning all. Just joined, hoping someone might be able to help ?? I have a 2009 RX400h - about 75k miles and, having bought it last summer, I'm absolutely loving it. However, just in the last couple of weeks I have noticed the footwell on the passenger side has become sodden..I've checked windows etc, and certain that seals all OK on doors and no sign of 'leaking' from anywhere above, yet it continues to be very wet. Any ideas what this is and what I can do about it ? Many thanks